How to balance a radiator

The heating system in many homes can sometimes not perform optimally, especially if the radiators are not properly balanced. This can mean that radiators on different floors can give out different levels of heat, even when they seem to be on the same setting, and some radiators might not heat up at all.

We look at ways to check whether your radiators need balancing and how to balance a radiator yourself with just a valve adjuster or a spanner.

Jump to:

• What does radiator balancing mean?
• What happens if radiators are not balanced?
• Signs that your radiators need balancing
• What causes unbalanced radiators?
• Is balancing radiators the same as bleeding them?
• What is the quickest way to balance your radiators?
• Step-by-step: Balance a radiator system

What does radiator balancing mean?

Radiator balancing is the process of adjusting radiator valves to help ensure that all the radiators in your home heat up at a similar speed. 
The way that many conventional heating systems work is that hot water, which is first heated by the boiler, is pumped through valves and down pipes to your radiators in the various rooms of the home. This hot water will heat the radiators up, and the radiators also return heat back to the boiler, through a separate return valve.

The radiators closest to the boiler will usually get the hot water faster and it then passes to the other rooms in the property. If the system is unbalanced, this can mean that some radiators in the system won’t get as much heat or may be considerably slower to heat up. 

What happens if radiators are not balanced?

The main problem that people experience if their radiators are not balanced is that some rooms in their home (often those furthest from the boiler) are colder than others, even if radiators are turned all the way up.

This is not only inconvenient, but it can also cost you more in energy bills. If some rooms don’t feel warm enough, most people will turn up their thermostat to compensate. However, an unbalanced system can mean that some rooms then get warmer than needed while others only just keep up, so your bills will be higher as your boiler is working harder and for longer.

An unbalanced radiator system means that your boiler will not be operating at optimal efficiency. 

Signs that your radiators need balancing

Different temperatures from different radiators

The most common sign that your radiators need to be balanced is if the radiator closest to the boiler generates lots of heat, but the radiator furthest away from the boiler feels noticeably cooler to the touch. This is with both radiators on the same setting.

In more extreme examples of an unbalanced heating system, it can be the case that one single radiator gets all of the heat, returns it to the boiler and none of the other radiators get warm at all. 

Boiler working overtime

Another sign that your radiators might need balancing could be if your boiler is working particularly hard over a long period of time i.e. it cycles on repeatedly. Usually, with a well-balanced system, the boiler would stop working as hard once the specified temperature is reached and only kick back in if the temperature in the home drops. With an unbalanced system, the different temperatures in different rooms can mean that the boiler continues to work, trying to bring the room temperature up in rooms with a radiator that isn’t producing enough heat to achieve it.

What causes unbalanced radiators?

There are a few different reasons that a radiator system might be unbalanced, including:

• When the system was fitted, balancing was not carried out initially by the installers, so it has never been properly balanced.
• If radiators have been temporarily removed for some reason and then reinstalled, e.g. for decorating or to be repaired or replaced, this can cause the system to lose its balance.
• If thermostatic radiator valves (TRVs) have been fitted that aren’t auto-balancing, this can cause loss of balance in a radiator system.

Is balancing radiators the same as bleeding them?

It can be easy to confuse the two, but balancing radiators and bleeding radiators are different processes that solve different problems.

Bleeding radiators involves opening a small valve on individual radiators to let out air that is trapped. Read our guide on how to bleed a radiator to find out more.

Balancing radiators involves adjusting a different valve that controls the flow of hot water through the entire system.

When balancing a radiator properly, you’ll have to check and potentially adjust every radiator in the system to solve the issue, whereas, with bleeding, you might only need to do this on one individual radiator to get it working as it should.

As well as bleeding or balancing radiators, you can also read about our other steps to radiator efficiency

What is the quickest way to balance your radiators?

Balancing radiators is absolutely a task that many people can do themselves quite quickly, even if they have no previous experience. 
If you’re happy to give balancing your radiators yourself a go, follow our step-by-step guide below. The only tool you need to balance radiators is an adjustable spanner.

However, if you don’t feel able to attempt to balance a radiator system on your own, you can get a professional heating engineer to do it for you. Make sure you always use a tradesperson that is Gas Safe registered. 

Step-by-step: Balance a radiator system

1. Turn off your heating and allow all radiators to cool down completely

To rebalance the system, you’ll need to work out which radiator gets the hot water from the boiler first, then the next one to get warm, and so on, for every radiator in your home. This is because when you balance the system, you’ll need to start with the one that gets warm first and work your way through in order to the one that gets warm last.

The easiest way to test it by turning your heating on from cold and following the heat around your home, checking which radiators get hot first. Firstly though, you need to make sure the valves are all open while your radiators are cold.

2. Open the valves on all of your radiators

You’ll need to open both the TRV (or on/off valve if you don’t have TRVs fitted) all the way, as well as the lockshield valve.

The lockshield valve is on the bottom of the radiator, on the opposite side to the on/off valve. It is usually covered with a plastic cap (the lockshield) to prevent the valve from accidentally being moved. Pop off the cap and you can see the valve, which can be moved using an adjustable spanner or a lockshield valve key. You’ll need to turn it anti-clockwise to open the valve fully.

3. Turn on your heating and note the order in which your radiators warm up

Usually, the radiators closest to the boiler will heat up first when all valves are open, but there can be some different installation types, so make sure you check which order the radiators get hot in and note this down for later. This can be an easier job for two or more people, especially if you have more than one storey to your home, so that you can quickly move between rooms to check you have the order correct. Be cautious not to burn yourself when checking.

4. Turn your heating off again

You’ll need to let your radiators all cool down totally before you move onto the next step.

5. Start to adjust the valves in order

• Starting with the radiator that got hot quickest in your test, close the valve all the way (clockwise) and then do a quarter of a turn the other way (anti-clockwise) to open it slightly.
• Moving to the next radiator on the list, fully close and then open this one’s lockshield valve very slightly more than you did the previous radiator.
• Repeat this in order for every radiator in your home, with each one having the lockshield valve slightly more open than the last.
• By the time you get to the final radiator to get warm in your earlier test, you can leave the lockshield valve open all the way.

6. Turn on your heating again and repeat the order test from earlier

While the closest radiator is still likely to get warm first, there should be a noticeable difference in how quickly the other radiators, especially the last one on your list, become warm. Your radiators are now balanced and should perform better, helping your whole heating system to work more efficiently.